William l



(No Model.)

W. L. FITCH.

AIR SUPPLY TO THE FEED WATER FOR STEAM BOILERS. No. 285,884.

Patented Oct. 2, 1883.

2 WE v UNITED STATES PATENT QEEICE.

XVIIJIJIAM L. FITCH, OFCHIUAG ILLINOIS, ASSIGNOR, BY DIRECT AN D MESNEASSIGNIVIENTS, TO D. H. FLETCHER, TRUSTEE, OF SAME PLACE.

AIR-SUPPLY TO THE FEED-WATER FOR STEAM-BOILERS.

SPECIFICATION forming part of Letters Patent No. 285,884, dated October2, 1883. Application filed December 23, 1852 (Nomodehl To all whom itmay concern:

Be it known "that I, lVlLipiAn t L. FITCH, a citizen of the UnitedStates, and residing at Chicago, in the county of Cook and State ofIllinois, have invented certain new and useful Improvements inAir-Supply to the Feed- \Vater for Steam-Boilers, which are fully setforth in the following specifications.

It has heretofore been observed that more IO heat is required to producea given pressure in a boiler from water from which all the air has beenexhausted by repeated boilings than from water which contains aconsiderable (111 antity of absorbed air, commonly called live water.

My invention consists in providing an economical method of introducingair into steamboilers, and in certain preferred forms of devices forputting that method into practice.

My method consists in charging the water, before it enters the boiler,with air to as great a degree as possible without preventing the properaction of the pump or other feeder which forces the water to the boiler.The preferred forms of device for so charging the water are hereinafterset forth. The extent to which the water may be so charged will varysomewhat with different feeders; but preferably the amount of airintroduced should not be more than the water will receive by absorptionor hold in minute globules, and without any strong ten dency to separatebefore the water reaches the boiler.

Figure 1 shows the application of my invention and device to asteam-pump employed to force water to a steam-boiler. Fig. 2 shows theapplication of the same invention and device to a feeder of the classknown as an in spirator.

A, Fig. is the pump-cylinder. A, Fig. 2, is a familiar form ofinspirator. B in each is the water-induct pipe. 7 is the dischargepipeleading to the boiler. D is an air-feed pipe, which opens into thewater-supply pipe B at any convenient point, preferably between thereservoir and the feeder, -pump or injector; but avalve, G, should beemployed, located bet-ween the reservoir and the air-feed pipe D,

to regulate the supply of water from the reservoir. Such a valve iscommonly employed, and it is not a part of my invention.

The air-feed pipe D may, in some circumstances, be located opcning intothe inspirator, as indicated by the outline H, between the primary andsecondary stcamjet of the inspi- 5 rator; or it may, though even lesspreferably, be connected between the inspirator or injector and theboiler, as indicated by the outline K but I deem the referable locationto be as first above describedbetween the reserx oir and the feeder. Inwhateverposition it is placed, the opening of the air-feed pipe D intothe water-supply pipe B should preferablybe controlled by a valve, E, bymeans of which the amount of air admitted may be regulated.

F is a check-valve in the air-feed pipe, which opens inward, admittingair when the'feeder is drawing water, and closing to prevent the escapeor discharge of water by pressure from the reservoir or otherwise at thecounter or forcing stroke of the pump-piston. \Vhen a pump is the feederemployed, orat any instant when the feeder is not drawing water throughthe water-induct pipe B, this valve is a con venience only, not anecessity. The action of 7 5 this device is that the current of waterdrawn by the feeder through the pipe B will induce a suction of airthrough the pipe D, the open ing into which may be so regulated by thevalve E that the amount of air taken shall be only such as the waterwill absorb or hold in suspension in minute globules, so not pre ventingthe action of the pump drawing by suction and not forming an air-cushionin the pump-cylinder sufficient to prevent the action 8 5 of thepump-piston forcing the water forward to. the boiler. hen an injectororiinspirator is the feeder employed, the difficulty abovesuggested,possible to arise in the use of a pump, will not be ekperienced, and theamount of air 0 taken will consequently not be so limited. The air thustaken passes with the water to the boiler, and, being there heated withthe water, adds its expansive force to that of the water, and, as provenby experience, makes it possible to obtain, with less water and lessconsump- Q asassr tion of fuel, a greater available force for motivepower and a greater amount of steam for heating purposes than if wateralone were fed to the boiler. r

' The purpose served by the valve E is to regulate the amount of airadmitted to the watersupply pipe in such ratio to the amount of Wateradmitted through the valve G that the maximum effectiveness of thecombination for steam or pressure producing purposes may be attained.Just at what point this maximum is found will vary with the varyingcircumstances of each case, as the character of the feeder employed, thepressure of steam maintained, the presence and character of impuritiesin the water, and, perhaps, other circumstances, and, besides, thepurpose and use to which the steam is being applied will be taken intoaccount. If dry steam is desired, more air will be taken, and if wetsteam less, and without special or further instruction any experiencedengineer will make the proper adjustment, according to the needs of thecase.

Air and water have heretofore been heated in the same boiler for thepurpose of securing the combined advantages of steam and hot-airpressure; but it has been usual to feed the air and water to the boilerby separate conduits, so requiring separate feeding devices andencountering other difficulties. The result has been that the amount ofpower expended to operate these devices has been nearly or quite equalto the gain effected by them.

The advantages of our method-viz., charging the water with air beforefeeding it to the boilerare economy of construction, simplicity ofoperation, and that absolutely no power additional to that required topump the water air, and thereby eases the pump, preventing the pounding,so often unavoidable when pumping solid water.

I claim, therefore, as my invention and desire to secure by LettersPatent- 1. The method of supplying air to steam- 5o boilers, whichconsists, substantially, in charging the feed-water, before it passes tothe boil-. er, with air. r

2. The method of charging with air the feedwater for steam-boilers,which consists in admitting the air in limited quantity to thewater-supply pipe to the feeder.

3. In the water-supply pipe to a feeder to a steam-boiler, an openingprovided for the purpose of admitting air thereto, controlled bysuitable valve or valves, substantially as set forth.

. 4-, In combination with the water-supply pipe B, the air-induct pipeD, provided with the valve E, substantially as and for the purpose setforth.

- 5. In the described air-inductor, and in combination therewith, thecheck-valve F, substantially as and for the purpose set forth.

In testimony that I claim the foregoing as my invention I have hereuntoset my hand in the presence of two witnesses.

\VM. L. FITCH.

, Attest:

\VM. D. SMITH, CHAS. S. BURTON.

